More than 25,000 participants are expected to compete Sunday in the 29th annual L.A. Marathon.
Defending men's champion Erick Mose of Kenya is among 16 competitors in the elite men's field.
Ethiopia's Amane Gobena, who finished second in 2009, is among 10 elite women's competitors.
Winners of the men's and women's races each receive $25,000.
A $50,000 "challenge" bonus also will be awarded to the first runner to cross the finish line. The women will start 17 minutes 41 seconds ahead of the men, nearly a minute less than the 18:35 advantage of last year, when Belarus' Aleksandra Duliba finished 2:09 ahead of Mose.
"We have to work together," Mose said of the men. "The ladies are strong."
Women have won the gender challenge six times, men four.
The 26.2-mile course begins at
Four-time defending champion Krige Schabort is among 12 men in the elite wheelchair division. There are four competitors in the women's elite field.
Winners in the wheelchair divisions receive $2,500.
Wheelchair races begin at about 6:55 a.m., elite women's runners at 7:10 and elite men at 7:25.
KTLA Channel 5 begins its television broadcast at 6 a.m. Radio station AM 570 begins coverage at 5 a.m.